Determination of Seniority

I am working as a Translator in Rajya Sabha. I joined on 18.05.2022. Before that I was working as Translator in SFIO. I got offer letter on 05.04.2022 and I resigned from SFIO on 08.04.2022 requesting to relieve me on 30.04.2022 but SFIO did not relieve me on 30.04.2022, SFIO relieved me on 17.05.2022 and I joined Lok Sabha on 18.05.2022. As per the terms and conditions Rajya Sabha I had to join within 1 month or else my seniority will be lost. Before deciding my seniority, Rajya Sabha Secretariat amended the rule of joining within 1 month and now as per the new rule, you were allowed to join within 2 months without loss of seniority, which I did.. Rajya Sabha Secretariat has fixed a provisional seniority list keeping me at 11th rank. But a Translator who is under me in the seniority list complained (only verbal not written) that seniority should be as per the terms and conditions given in the offer letter. I want to know whether my seniority will be decided by the old rules or the new rules because new rules came before fixation of my seniority. whether my seniority could be lost due to the negligence of SFIO, not mine.